:root {
  --background-color: #2a3d50;
  --ball-color1: #08a2e9;
  --ball-color2: #091a47;
}

* {
  margin: 0;
  padding: 0;
}

body {
  width: 100vw;
  height: 100vh;
  background-color: var(--background-color);
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: Shijie;
}

@font-face {
  font-family: "Shijie";
  src: url("../intro3S/汉仪正圆-45S.ttf");
}

.box {
  width: 400px;
  height: 400px;
  background-color: #fff;
  position: relative;
}

.ball {
  position: absolute;
  width: 160px;
  height: 160px;
  background:radial-gradient(circle at 50px 50px,var(--ball-color1),var(--ball-color2));
  border-radius: 50%;
  top: 10px;
  left: 50%;
  transform: translate(-50%);
  animation: jump 1s ease-in-out infinite;
  z-index: 2;
}

@keyframes jump {
  0%,
  100% {
    top: 10px;
  }
  50% {
    top: 200px;
  }
}
.shadow {
  position: absolute;
  width: 100px;
  height: 100px;
  background-color: #040f1f;
  top: 90%;
  left: 50%;
  transform: translate(-50%, -50%) rotateX(70deg);
  filter: blur(20px);
  border-radius: 50%;
  z-index: 1;
  animation: change 1s ease-in-out infinite;
}

@keyframes change{
  0%,100%{
    width: 100px;
    height: 100px;
    opacity: 0.5;
  }
  50%{
    width: 80px;
    height: 80px;
    opacity: 1;
  }
}
